Evolutionary characterization and pathogenicity of Getah virus from pigs in Guangdong Province of China.

Getah virus (GETV) is an emerging zoonotic virus that can infect humans and many mammals through mosquitoes. In this study, a novel pathogenic GETV strain, GDQY2022, was isolated from a pig farm in Guangdong Province, China. Sequence comparisons and phylogenetic analysis showed that GDQY2022 belongs to group III (GIII) and was most closely related to strain HeN202009-2, with 99.78% nucleotide sequence identity. Histopathological examination revealed significant pathological changes, such as widened alveolar septum in the lungs with mild congestion and hemorrhage. Differences in viral load between tissues were assessed by real-time RT-PCR, and significantly higher levels of GETV were found in abdominal lymph nodes and lungs of subclinically and clinically affected pigs (P < 0.01). This study provides valuable data for understanding the risk of GETV infection in the pig industry and a reliable basis for studying the pathogenic mechanisms and diagnostic surveillance of GETV.

Emergence of human-porcine reassortment G9P[19] porcine rotavirus A strain in Guangdong Province, China.

Group A rotaviruses of the family Reoviridae is one of the important intestinal pathogens causing diarrhea in piglets and humans. A human-porcine reassortment rotavirus, GDJM1, was identified from outbreak of diarrhea in suckling piglets and it associated with 60.00% (324/540) morbidity and 20.99% (68/324) mortality in Guangdong Province of China in 2022. Thus, to further characterize the evolutionary diversity of GDJM1, all gene segments were analyzed. The genome constellation was G9-P[19]-I5-R1-C1-M1-A8-N1-T1-E1-H1. Nucleotide sequence identity and phylogenetic analyses showed that the VP6, VP7, NSP4 and NSP5 genes of GDJM1 were the most closely related to the respective genes of porcine strains, with the highest homology ranging from 95.65-98.55% identity. The remaining seven genes (VP1-VP4, NSP1-NSP3) were the most closely related to human strains, with the highest homology ranging from 91.83-96.69% similarity. Therefore, it is likely that GDJM1 emerged as the result of genetic reassortment between porcine and human rotaviruses. To our knowledge, this is the first report that a human-porcine reassortment G9P[19] RVA strain has been identified in mainland China, which providing important insights into evolutionary characterization of G9P[19] RVA strain, and reveals that the strain has a potential risk of cross-species transmission.